Exam 21: Electric Current and Direct-Current Circuits

Four resistors are connected across an ideal dc battery with voltage V,as shown in the figure.If the total current in this circuit is I = 1 A,what is the value of the voltage V?

If V = 20 V and the battery is ideal,what is the current through R₃ in the figure?

How much current will be flowing through a 57.0mm. Length of copper wire with radius 0.0mm If it is connected to a source supplying 62.0V? The resistivity of the metal is 1.68 × 10^-8 Ω ∙ m.

A 4.0-Ω resistor is connected to a 12-Ω resistor and this combination is connected to an ideal dc power supply with voltage V as shown in the figure.If the total current in this circuit is I = 2.0 A,what is the value of voltage V?

Suppose you have two capacitors and want to use them to store the maximum amount of energy by connecting them across a voltage source.You should connect them

A portion of a circuit is shown in the figure,and the batteries are ideal.What is the potential difference V_A - V_B if I = 5.0 A?

The network shown is assembled with uncharged capacitors X ,Y,and Z,with C_X = 4.0 μF,C_Y = 6.0 μF,and C_Z = 5.0 μF.The switches S₁ and S₂ are initially open,and a potential difference V_ab = 120 V is applied between points a and b.After the network is assembled,switch S₁ is then closed,but switch S₂ is kept open.What is the final potential difference across capacitor X?

If a quantity you calculated has units of Ω ∙ m what is that quantity?

When two or more different capacitors are connected in parallel across a potential source (battery),which of the following statements must be true? (There could be more than one correct choice. )

Three 2.0-Ω resistors are connected to form the sides of an equilateral triangle ABC as shown in the figure.What is the equivalent resistance between any two points,AB,BC,or AC,of this circuit?

The nichrome heating element in an electric drier operates on 240 V and generates heat at the rate of 2.0 kW.The heating element shorts out and,in repairing it,the repairman shortens the nichrome wire by 10%.(Assume the temperature is unchanged.In reality,the resistivity of the wire will depend on its temperature. )What effect will the repair have on the power dissipated in the heating element?

A 5.0-μF capacitor and a 7.0-μF capacitor are connected in series across an 8.0-V potential source.What is the potential difference across the 5.0-μF capacitor?

If emf of the ideal battery is V = 100 V,what is the potential difference across R₅ for the circuit shown in the figure?

A number of resistors are connected across points A and B as shown in the figure.What is the equivalent resistance between points A and B?

If we double the resistance in a circuit but keep the current in it constant,the power dissipated by that circuit will

A 4.0-Ω resistor is connected with a 12-Ω resistor and both of these are connected across an ideal dc power supply with voltage V as shown in the figure.If the total current in this circuit is I = 2.0 A,what is the current through the 4.0-Ω resistor?

A 4000-Ω resistor is connected across a 220-V power source.What current will flow through the resistor?

How much does it cost to operate a 25-W soldering iron for 8.0 hours if energy costs 8.0¢/kWh?

If V = 40 V and the battery is ideal,what is the potential difference across R₁ in the figure?

An ideal 10.0-V dc is connected across a Resistor in series with an Resistor.What is the potential drop across the Resistor?